Chlorophyll fluorescence imaging for non-invasive assessment of plant stress responses: Methodological advances and applications in precision agriculture

Abstract

Chlorophyll fluorescence imaging has emerged as a powerful non-invasive technique for assessing plant photosynthetic performance and stress responses with unprecedented spatial and temporal resolution. This study presents optimized protocols for pulse-amplitude modulation (PAM) fluorometry combined with thermal imaging for integrated plant stress phenotyping. Maximum quantum yield (Fv/Fm) decreased from 0.83 under control conditions to 0.71, 0.68, 0.72, and 0.58 under drought, heat, salt, and combined stress respectively. Non-photochemical quenching (NPQ) showed compensatory increases reaching 3.52 under combined stress. Machine learning classification achieved 94.2% accuracy in identifying stress type from fluorescence signatures.